<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<style>
			.box1{
				width:200px;
				/* height: 200px; */
				background-color: #ABDCFF;
			}
			
			.box2 {
				float:left;
				width:100px;
				height: 100px;
				background-color: #D3D3D3;
			}
			
			.box2::after, .box2::before{
				content: "";
				clear: both;
				display:table-cell;
			}
			
			.box3{
				width:100px;
				height: 100px;
				background-color: #ddd;
			}
			
		</style>
	</head>
	<body>
		<div class="box1">
			<div class="box2">box2</div>
		</div>
		
		<div class="box3"></div>
	</body>
</html>
